Re: My new mill

Andrew Werby wrote:

> From: Andrew Werby <drewid@...>
>
> [I just got my new (old) mill delivered yesterday, and it's really a beast!
> This is a Ramco "Ramill", built to be a CNC mill in the mid-eighties. It
> has servo motors and ballscrews, which should save me some time and money
> over retrofitting an old Bridgeport, which was my first idea. Currently, it
> will accept instructions in g-code, either from the attached keyboard or
> from a tape drive. But I'd like to convert it to a more modern control
> system which wouldn't be limited to 999 instructions- some of the progams
> I've been generating run over 2 megs, (and I'm just getting started.) I
> think I can save the servo amplifiers and most of the relay switches, while
> gutting out the old computer and attaching a standard monitor. I'd be happy
> with something that ran in real time under DOS, if it could handle g-code.

I would suggest EMC. It runs under Linux, but Linux offers total MSDOS
file system compatibility. You can run text-based DOS programs in an
emulator window, as well as read and write DOS floppies directly in
Linux. In fact, if you mount a DOS floppy before starting EMC (or
later, using another window) you could execute a G-code program
directly off the floppy, if you wanted to.

The reason DOS is unacceptable, is that it is NOT a real-time environment.
Yes, it seems pretty real time to us slow humans, but for a motion
control system with a 1 KHz servo update rate (or better) DOS is
most emphatically NOT real-time. You would have to place hooks
on every interrupt entry point and write your own real-time
scheduler to get guaranteed priority for the realtime task. But,
the worst part is that the DOS environment is not secure!
Any haywire program could overwrite the motion control
code or data areas, and cause a hazardous crash! I sure wouldn't
use such a system!

See my page at : http://ascc.artsci.wustl.edu/~jmelson/CNCconv.html
and http://ascc.artsci.wustl.edu/~jmelson/EMC.html

For EMC itself, see :
http://www.isd.cme.nist.gov/projects/emc/emcsoft.html

The software is available for download from the web.

The only thing it sounds like you'd need to buy would be the
Servo-to-Go card, and maybe a rack of solid-state relays to
drive the auxilliary stuff.

Servo-to-Go is at : http://www.servotogo.com/

If you have any questions, feel free to email me.

Jon